Theoretical and quasi-practical disclosures are set forth in least U.S. Pat. No. 4,200,144 and 4,188,795 as to means whereby three or even more reversibly hydridable materials can be used at two or more temperatures to raise the pressure of hydrogen for heat transfer purposes. There are, of course, other uses to which high pressure hydrogen can be put and the inherent characteristics of an adsorption-desorption hydrogen compressor are advantageous. Despite this, to applicants' knowledge, no one has as yet provided the art with a hydrogen compressor of practical, inexpensive, safe design which can operate on the energy present in widely available waste heat streams, i.e., hot water at temperatures between about 50.degree. C. and 100.degree. C.
Because no one has as yet provided the art with such a practical absorption-desorption hydrogen compressor, the art has used mechanical compressors which are noisy and which wear out fast because of high speed of operation and difficulty with lubrication. Compared to a prototype compressor of the present invention, a comparable mechanical compressor is 3 times its volume, 5 times its weight and twice its cost.